FSX is a fairly sluggish, poorly optimized simulation with an excessive reliance on CPU clock speed. The only real "cure" for poor performance is a fast CPU. That being said, there are many ways to make things far far worse, including improper FSX settings.There are countless tips and tricks floating around the internet which claim to be the end-all-be-all of FSX performance tweaking. In most cases these turn out to be highly specific to one individual's system or aircraft, or even make things worse.

Many also argue the benefits of running in DX10 "preview" mode. The ONLY benefit you'll see from doing this is if light bloom and aircraft self-shadowing are enabled. However please don't be fooled into thinking that running DX10 preview will globally increase performance regardless of your graphic options - it will not. You'll get better performance from DX9 except in the case of the aforementioned options being enabled. Furthermore, the quirks (e.g. z-buffer errors, slower texture loading, etc), seldom outweigh any benefits. FSX was designed to run under DX9. Unless you must use self-shadowing and/or light bloom, there's zero benefit to using this beta mode. Bottom line, try it for yourself and see what works best for you.

We've found one script which seems to provide very good optimization in most cases, and if you follow instructions, it's also safe, as it backs up your FSX.cfg. Note that we cannot take responsibility for anything that may go wrong, but if you're looking for a simple solution that works most of the time, try this: http://www.venetubo.com/fsx.html

SUPERBUG-SPECIFIC PERFORMANCEYou can improve Superbug performance in a number of ways via the Aircraft manager. Go to Preferences (tab), and select Simulation from the left. As with anything else, you must decide if the improvement in performance is worth the price in terms of reduced visual quality or reduction in features. The following features are listed by significance, where option of low significance are least likely to affect performance in any measurable way. Options which are insignificant are not listed.

Fuselage:This option controls the display of external aircraft parts such as wings, fuselage, airbrakes and tail surfaces which would be visible from the virtual cockpit. Although the displayed parts are very lean in terms of geometry, additional textures must be loaded, and this may improve performance on systems lacking sufficient video memory.Category: GPUSignificance: LOW

External Stores:If external aircraft parts are enabled, this option will add weapon geometry to the wing tips and outer pylons which would be visible from the virtual cockpit. Note that these weapons will correspond to your current loadout. Disabling this option may marginally improve performance.Category: GPUSignificance: LOW

Engine Smoke Effect:Modern jet aircraft burn fairly clean, but small amounts of smoke can be seen, particularly when viewed parallel to the engines. However smoke effects can be expensive on some graphics cards due to excessive transparency and a large particle count. This option should be off.Category: GPUSignificance: HIGH

Lite LDDI: (v1.2 or less, no longer applicable in 1.3+)Removes some tactical [TAC] functions (including radar display) from the LEFT DDI. Generally the LEFT DDI is used for support functions in RL; enabling this option will remove redundant radar functions which are available on other displays. This will free resources, improving frame rates.Category: CPUSignificance: MEDIUM

Lite RDDI: (v1.2 or less, no longer applicable in 1.3+)Removes some support [SUPT] functions (including the HSI display) from the RIGHT DDI, freeing resources. Generally the RIGHT DDI is used for tactical functions in RL; enabling this option will remove redundant HSI functions which are available on other displays. This will free resources, improving frame rates.Category: CPUSignificance: MEDIUM

Lite UFCD:This option removes all DDI functions from the UFCD. Since the DDI mode is redundant with a functioning LDDI and RDDI, it is recommended that you leave this option checked (light version). The DDI functions use a tremendous amount of resources and this will improve performance.Category: CPUSignificance: HIGH

RapidRaster:When checked, enables VRS Rapid Rasterization technology (BETA) for the MPCD moving map. RapidRaster allows full gamma control (via brightness knob), virtually instantaneous transformations, and will eventually support external data sources such as streaming sectionals. Note that RapidRaster WILL currently impact frame rates significantly compared to the standard GPS map.Category: CPUSignificance: HIGH